Polar orientation induced by local photo-assisted poling in azo copolymer films

摘要

Polar orientation created by local photo-assisted poling (PAP) in copolymer films containing disperse red 1 was investigated by scanning probe microscopy. PAP was performed by a proximal biased probe, and the polar orientation was semiquantitatively measured by electrostatic force microscopy. The polar orientation behaves as a biexponential function of the period of PAP, which is dominated by fast angular hole burning and slow angular redistribution (AR). The characteristic time of AR decreases linearly with the poling bias. An expression has been developed to interpret the evolution of the Lorentzian-like shape of the poled spots. A poled spot with 150 nm FWHM was demonstrated.